We expect to complete the comparative study of endocytosis in erythrocytes and their ghosts and also to begin a study of nonenergy-requiring vacuolation in erythrocytes and ghosts. We expect to continue our studies on the activator of the Ca2 ion dependent ATPase, to incorporate it into resealed ghosts and observe its effect on vacuolation, and to begin to purify the Ca2 ion ATPase. Purification of this ATPase will allow us to determine whether there is only one such ATPase in the erythrocyte and whether it is functionally restricted only to Ca2 ion movement or whether it might also be involved in vacuolation. We intend to observe the effect of extracorporeal incubation of whole cells on the vacuolation of ghosts prepared from them. We expect to continue our studies on the phosphorylation of phosphatidylinositol, completing them and showing the relationship between this phosphorylation and endocytosis. We also intend to carry out studies on spectrin phosphorylation, to observe whether it is directly involved in endocytosis or not.